European Eyewear Safety norms

K	Anti Scratch: resistance to surface deterioration by fine particles.
N	Anti Fog: fog resistance. For the eyepieces to comply, they must remain free of fog for a minimum of 8 seconds at 100°C.
1	Continuous work - Permanent wearing
F	Low energy impact, resists a 6 mm ball and 0.86 g at 45 m/s.
B	Medium energy impact, resists a 6 mm ball and 0.86 g at 120 m/s.
T	Impact resistance at extreme temperature, -5° (± 2°) & 55° (±2°)
9	Molten metal and hot solids
C	unaltered colour perception
2-1.2 / EN 170	Clear eyepiece filter filtering 99% of UV rays, for indoor work / in accordance with EN 170 (Ultraviolet filters)
5-3.1/ EN 172	Tinted eyepiece filter filtering 99% of UV rays, for outdoor work / in accordance with EN 172 (Sun protection filters for industrial use)

EN 166:2001	Guarantee of minimum resistance of the protection to common risks related to personal protective equipment regarding safety, comfort and strength.
3	Protection against droplets or splashing liquids.
4	protection against large spray particles > 5 microns.
F	Low energy impact, resists a 6 mm ball and 0.86 g at 45 m/s.
B	Medium energy impact, resists a 6 mm ball and 0.86 g at 120 m/s.
T	Impact resistance at extreme temperature, -5° (± 2°) & 55° (±2°)
9	Molten metal and hot solids.